<template>
  <div class="goods">
    <div class="menu-wrapper" ref="menuWrapper">
      <ul>
        <li v-for="(item, index) in goods" :key="index"
            @click="selectMenu(index, $event)"
            class="menu-item" :class="{'current': currentIndex === index}">
          <span class="text border-1px">
            <span v-show="item.type>0" class="icon" :class="classMap[item.type]"></span>{{item.name}}
          </span>
        </li>
      </ul>
    </div>
    <div class="foods-wrapper" ref="foodsWrapper">
      <ul>
        <li v-for="(item, index) of goods" :key="index"
            class="foods-list foods-list_js">
          <h1 class="title">{{ item.name }}</h1>
          <ul>
            <li @click="selectFood(food, $event)" v-for="(food, idx) of item.foods" :key="idx" class="foods-item border-1px">
              <div class="icon">
                <img :src="food.icon" width="57" height="57" alt="">
              </div>
              <div class="content">
                <h2 class="name">{{ food.name }}</h2>
                <p class="desc">{{ food.description }}</p>
                <div class="extra">
                  <span class="count">月售{{food.sellCount}}份</span><span
                >好评率{{food.rating}}%</span>
                </div>
                <div class="price">
                  <span class="now">￥{{ food.price }}</span>
                  <span class="old" v-show="food.oldPrice">￥{{ food.oldPrice }}</span>
                </div>
                <div class="cartcontrol-wrapper">
                  <m-cartcontrol @add="addFood" :food="food"></m-cartcontrol>
                </div>
              </div>
            </li>
          </ul>
        </li>
      </ul>
    </div>

    <m-shopCart ref="shopcart" :select-foods="selectFoods" :delivery-price="seller.deliveryPrice"
                :min-price="seller.minPrice"></m-shopCart>

    <m-food @add="addFood" :food="selectedFood" ref="food"></m-food>
  </div>
</template>

<script type="text/ecmascript-6">

import BScroll from 'better-scroll';
import mShopCart from 'components/m-shopcart/m-shopcart';
import mCartcontrol from 'components/m-cartcontrol/m-cartcontrol';
import mFood from 'components/m-food/m-food';

const ERR_OK = 0;
export default {
  props: {
    seller: {
      type: Object
    }
  },
  data () {
    return {
      goods: [],
      listHeight: [],
      scrollY: 0,
      selectedFood: {}
    };
  },
  computed: {
    currentIndex () {
      for (let i = 0; i < this.listHeight.length; i++) {
        let height1 = this.listHeight[i];
        let height2 = this.listHeight[i + 1];
        if (!height2 || (this.scrollY >= height1 && this.scrollY < height2)) {
          return i;
        }
      }
      return 0;
    },

    selectFoods () {
      // 观测的是 goods 对象，子组件向父组件传值
      let foods = [];
      this.goods.forEach((good) => {
        good.foods.forEach((food) => {
          if (food.count) {
            foods.push(food);
          }
        });
      });
      return foods;
    }
  },
  created () {
    this.classMap = ['decrease', 'discount', 'special', 'invoice', 'guarantee'];

    this.$http.get('/api/goods')
      .then((res) => {
        res = res.data;
        if (res.errno === ERR_OK) {
          this.goods = res.data;

          // vue 更新数据是异步的 在 nextTick 中才能正确获取 DOM 高度
          this.$nextTick(() => {
            this._initScroll();
            this._calculateHeight();
          });
        }
      })
      .catch((err) => {
        console.log('err: ', err);
      });
  },
  methods: {
    selectFood (food, event) {
      if (!event._constructed) {
        return;
      }

      this.selectedFood = food;

      this.$refs.food.show();
    },

    selectMenu (index, event) {
      if (!event._constructed) {
        return;
      }

      let foodList = this.$refs.foodsWrapper.getElementsByClassName('foods-list_js');
      this.foodsScroll.scrollToElement(foodList[index], 300);
    },

    _initScroll () {
      this.menuScroll = new BScroll(this.$refs.menuWrapper, {
        click: true
      });

      // probeType: 实时派发滚动的位置
      this.foodsScroll = new BScroll(this.$refs.foodsWrapper, {
        probeType: 3,
        click: true
      });

      this.foodsScroll.on('scroll', (pos) => {
        this.scrollY = Math.abs(Math.round(pos.y));
      });
    },

    _calculateHeight () {
      // foodsWrapper 下所有指定类名的子元素
      let foodList = this.$refs.foodsWrapper.getElementsByClassName('foods-list_js');
      // console.log('[foodList]', foodList);
      let height = 0;
      this.listHeight.push(height);
      for (let i = 0; i < foodList.length; i++) {
        let item = foodList[i];
        height += item.clientHeight;
        this.listHeight.push(height);
      }
    },

    addFood (target) {
      this._drop(target);
    },

    _drop (target) {
      // 体验优化 异步执行下落动画
      this.$nextTick(() => {
        this.$refs.shopcart.drop(target);
      });
    }
  },

  components: {
    mShopCart,
    mCartcontrol,
    mFood
  }

  /*  events: {
        'cart.add' (target) {
          this._drop(target);
        }
      } */

};
</script>

<style scoped lang="stylus" rel="stylesheet/stylus">
  @import "../../common/stylus/mixin.styl";

  .goods {
    display flex
    position absolute
    top 174px
    bottom 46px
    width 100%
    overflow hidden

    .menu-wrapper {
      flex 0 0 80px
      width 80px
      background #f3f5f7

      .menu-item {
        display table // 垂直居中
        height 54px
        width 56px
        padding 0 12px
        line-height 14px
        &.current {
          position relative
          z-index 10
          margin-top -1px
          background #fff
          font-weight 700
          .text {
            //border-none()
          }
        }
        .icon {
          display inline-block
          vertical-align top
          width 12px
          height 12px
          margin-right 2px
          background-size 12px 12px
          background-repeat no-repeat

          &.decrease {
            bg-image('decrease_3')
          }
          &.discount {
            bg-image('discount_3')
          }
          &.guarantee {
            bg-image('guarantee_3')
          }
          &.invoice {
            bg-image('invoice_3')
          }
          &.special {
            bg-image('special_3')
          }
        }
        .text {
          display table-cell
          width 56px
          vertical-align middle
          border-1px(rgba(7, 17, 27, 0.1))
          font-size 12px
        }
      }
    }
    .foods-wrapper {
      flex 1
      .title {
        padding 14px
        height 26px
        line-height 26px
        border-left 2px solid #d9dde1
        font-size 12px
        color rgb(147, 153, 159)
        background #f3f5f7
      }
      .foods-item {
        display flex
        margin 18px
        padding-bottom 18px
        border-1px(rgba(7, 17, 27, .1))
        &:last-child {
          border-none()
          margin-bottom 0
        }
        .icon {
          flex 0 0 57px
          margin-right 10px
          font-size 0
        }
        .content {
          flex 1
          .name {
            margin 2px 0 8px 0
            height 14px
            line-height 14px
            font-size 14px
            color rgb(7, 17, 27)
          }
          .desc, .extra {
            line-height 10px
            font-size 10px
            color rgb(147, 153, 159)
          }
          .desc {
            margin-bottom 8px
            line-height 12px
          }
          .extra {
            & .count {
              margin-right 12px
            }
          }
          .price {
            font-weight 700
            /*font-size 24px*/
            /*font-size 0*/
            line-height 24px
            .now {
              margin-right 8px
              font-size 14px
              color rgb(240, 20, 20)
              line-height 1
            }
            .old {
              text-decoration line-through
              font-size 10px
              color rgb(147, 153, 159)
              line-height 1
            }
          }

          .cartcontrol-wrapper {
            position: absolute
            right 0
            bottom -6px
          }
        }
      }
    }
  }
</style>
